Many domestic garden water taps employ a compression-type valve, whereby the turning of a tap handle forces a disc washer or jumper valve onto a valve seat, thus preventing the flow of water through the valve seat. Such valves are mechanically simple, cheap, and reliable.
As the valve ages, the washer and the valve seat both deteriorate. This can cause leakage of water though a closed tap. In order to prevent this, where the deterioration is minor, the valve can generally be closed by additional tightening of the handle.
Such tightening can be difficult for those without sufficient strength, such as the aged or infirm. In order to overcome this problem, there are several mechanical devices available to assist the aged or infirm in the opening and closing of tap valves. Often, however, the use of these devices can be both cumbersome and inconvenient.
Additionally, the deterioration requires relatively frequent replacement of worn washers. When washers are not replaced, wastage of water due to tap leakage can be significant.
It is desirable to provide a garden tap which can be readily operated by the aged or infirm without the need for additional mechanical assistance. Such a tap should readily close, without a propensity for leakage. It should also be arranged such that the degree of opening can be easily adjusted, in order to vary the flow rate of water passing through the tap.
The present invention seeks to meet these desiderata.